Taking into account what Laurent said, the amount increasing so much when loaded into RAM implies that you use a decent compression. 119mb of compressed image data seems like an excessive amount for a small game.
First, you should try reducing the number of images. If your player can e.g. use a custom color for the character and you created 100 images in different colors, try using one image for the "naked" character and a second one for the colored overlay, which is drawn on top with the help of
sf::Sprite::setColor.
Second, if you really need all the images you still probably don't need them all at once. Load only the textures that you need for the current level, free the resources before loading the next level, if that makes any sense for your game.